br: check the correct changefeed info when restore/import data (#47322)

[ti-chi-bot]

This is an automated cherry-pick of #47322

What problem does this PR solve?

Issue Number: close pingcap/tiflow#9807

Problem Summary:

1. cdc will generate __backup__ changefeed key after upgrade from v6.1. and the check cannot handle it right now.

What is changed and how it works?

1. make check-requirements can skip the cdc change feed check.
2. fix the issue that br can handle migration key in etcd after cdc upgrade from v6.1.

Check List

Tests

• Unit test
• Integration test
• Manual test (add detailed scripts or steps below)
• No need to test

  • I checked and no code files have been changed.

Side effects

• Performance regression: Consumes more CPU
• Performance regression: Consumes more Memory
• Breaking backward compatibility

Documentation

• Affects user behaviors
• Contains syntax changes
• Contains variable changes
• Contains experimental features
• Changes MySQL compatibility

Release note

Please refer to Release Notes Language Style Guide to write a quality release note.

fix the issue that br can handle migration key in etcd after cdc upgrade from v6.1.

[ti-chi-bot]

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Adding the do-not-merge/cherry-pick-not-approved label.

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[ti-chi-bot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: 3pointer, Leavrth

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• OWNERS [3pointer,Leavrth]

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[ti-chi-bot]

[LGTM Timeline notifier]

Timeline:

• 2023-11-20 08:07:01.242726972 +0000 UTC m=+218849.907953166: ☑️ agreed by 3pointer.
• 2023-11-20 08:08:16.421815139 +0000 UTC m=+218925.087041333: ☑️ agreed by Leavrth.

[codecov]

Codecov Report

❗ No coverage uploaded for pull request base (release-6.5@f961aa5). Click here to learn what that means.
The diff coverage is n/a.

Additional details and impacted files

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